The invention pertains to a method for the torque-oriented control of an internal combustion engine, in which a sum torque is calculated from a set torque value and a friction torque, and in which a set injection quantity for controlling the internal combustion engine is calculated from the sum torque and an actual rpm value on the basis of an efficiency map.
A similar method is known from DE 10 2004 001 913 A1. In this method, the set torque value is determined from an input variable representing the desired power output. In the case of a motor vehicle application, this input variable corresponds to the position of a gas pedal, to which the set torque value is assigned by way of a characteristic curve. In the case of a generator application, the desired power output corresponds to a set rpm value, such as 1,500 rpm in the case of a 50-Hz generator application. In the case of a ship application, the input variable corresponds to the position of a selector lever selected by the operator. In the case of generator or ship applications, the rpm value of the internal combustion engine is regulated automatically. For this purpose, a control deviation between the set rpm and the actual rpm value is calculated, and the set torque value is determined as an actuating variable by way of an rpm controller.
Abrupt load changes at the power takeoff of the internal combustion engine are difficult to deal with. For example, the actual rpm's increase significantly when a ship's drive rises out of the water. When the drive becomes immersed again, the reverse phenomenon occurs; that is, the actual rpm's drop to a value considerably below the set rpm value. When the actual rpm value exceeds a certain limit, an “emergency stop” can be triggered. Known measures for improving this situation include changing the time at which injection begins and introducing an additional torque-limiting controller. Under normal operating conditions, this controller limits the actuating variable of the rpm controller and does not become dominant again until after the ship's drive is immersed again. A similar control circuit design and a similar method are described in DE 199 53 767 A1. No additional measure is provided to deal with load shedding.